DE 101 34 828 B4 discloses a wire-forming machine in the form of a leg spring machine, wherein a multiplicity of tools are arranged on one plate. Each tool has a base plate and is provided with its own drive assigned only to the particular tool and whose actuation allows the tool to be moved radially towards the wire or away from it. The base plates can be coupled to a ring which can be swiveled around the wire's axis and via which a fine adjustment of the tools relative to the wire can be achieved during the manufacturing process (swing axle). However, in this disclosed machine, each tool is provided with its own drive, which makes the machine complex and expensive.
DE 103 42 451 A describes a leg spring machine, wherein the tool units are arranged on a round vertical table and can be mounted to the round vertical table in any angular position. A central driving wheel which drives camshaft blocks, wherein the camshaft blocks can be connected to the tool units in the sense of a cam drive, is provided for driving the movement of the tool units. Although, in this case, not every tool unit requires its own, exclusively assigned drive, the time sequence of the movements is not sufficiently freely programmable.
The wire-forming machine according to DE 199 38 905 B4 is again a leg spring machine, which comprises two turrets mounted next to the wire guide. The turrets are arranged on a 3D cross table and can thus be positioned anywhere in space. In addition, the turret can also be rotated about an axis parallel to the wire axis, so that different tools can be made to engage the wire at different positions. In this disclosed machine, however, the changing of tools is very slow and limits the performance of the machine considerably. Moreover, the machine disclosed in DE 199 38 905 B4 needs more room than conventional leg spring machines.
DE 299 13 014 U discloses a shaping unit in module form for wire-bending machines, the module of the unit consisting of a base plate with a drive, a linear guide and a slider crank. The shaping units can be simply mounted to a machine wall and dismounted from it again. However, there is a disadvantage in that each tool unit has its own drive assigned to it again, which in turn makes the machine expensive, in particular in case of large number of tools.
The leg spring machine of EP 1 637 251 A works with a feeding unit mounted either to a 2D or a 3D cross table. This allows the wire to be transported to the radially mounted tools; however, this requires movement of very large masses. Therefore, the performance and rigidity of the disclosed machine are reduced.
A further leg spring machine comprising a two-dimensionally movable feeder is disclosed in DE 697 15 953 T for optimal positioning of the wire relative to the tool. In this case, the tool head is arranged above the feeder and can be moved both horizontally and vertically. In addition, a rotary axis for the tool is also provided. However, the machine disclosed in DE 697 15 953 T allows only one tool to be mounted to the tool head. A separate tool unit is needed for cutting. The arrangement of the tool head is fixed in advance, namely, vertically from above.
A leg spring machine of the above-mentioned type is disclosed in JP-P2007-30038A. The tool table is linearly displaceable along a first direction on a second plate, which is in turn linearly displaceable along a second direction relative to the machine frame, the first direction extending horizontally and said second direction extending vertically with respect to the longitudinal axis of the machine. However, practical experience has shown that the machine disclosed in JP-P2007-30038A is subject to very strong vibrations during operation and considerable shaking of the entire machine occurs. The vibrations and shaking leads to highly undesirable vibrations at the respective, already produced, bent-wire parts, thus unfavorably influencing the entire coiling or winding process, respectively.
In view of the above, there is a need for a wire-forming machine which is simple in construction, low-vibrating during operation, and allows for achievement of high operative performance.